They won't buffalo DJT, and eventually the investigators will be the investigated.
Let's hope so, but so far the only ones arrested in this whole scandal have only Trump associates.
To me, the only true solution is to appoint a non-DOJ person to investigate potential crimes by the DOJ. At least that's the best chance we'll get an honest result, and not a cover up.
But if that doesn't happen, firing Rosenstein (or Sessions) is politically more palatable than firing Mueller directly.